Ischemia describes a situation in which the flow of oxygen-rich blood is restricted. It can occur in many areas of the body. Reduced blood flow to the brain, for example, is called cerebral ischemia, which can lead to a “mini-stroke” (transient ischemic attack) or full ischemic stroke. Ischemia in the liver and kidneys are called hepatic ischemia and renal ischemia, respectively. In the legs ischemia can cause pain when walking (claudication) or even more severe problems such as gangrene and tissue death (necrosis).

Cardiac ischemia refers to reduced blood flow to arteries around the heart (coronary arteries), usually the result of the buildup of plaque (atherosclerosis). In many cases, ischemia has no symptoms (silent ischemia). In these patients, it is important to identify the ischemia before a major heart-related health concern, such as heart attack or sudden cardiac death, occurs. The American Heart Association estimates that between three and four million Americans have silent cardiac ischemia.

Other patients experience a kind of chest discomfort or pain (called angina) with their ischemia. Episodes of angina may last between 2 and 20 minutes. The discomfort or pain is often described as “crushing” or “heaviness.” 

Minor episodes of cardiac ischemia tend to cause little long-term damage to the heart, but there may be serious side effects in some patients:

Because of the potentially harmful effects of cardiac ischemia, researchers have thoroughly investigated both its symptoms and available strategies for diagnosing, treating and preventing it.